How it works:
When a customer is ready to make a purchase, they’ll see two options. They can pay with their credit card or through their PayPal account Paying with a Credit or Debit Card Step-by-Step:

Your Site: A customer chooses to pay with a Credit Card.
Your Site They enter shipping info on your site.
Your Site They enter their credit card details.
Your Site They review their payment info.
Your Site Their payment is processed.
PayPal.com You get paid. (The fun part.)